Let's talk about the hanna meters....

[sowellj]

Anyone able to try the 1:1 dilution with the 1ppm standard and their tankwater (assuming the tankwater reads 0)?

 

[Troylee]

Anyone able to try the 1:1 dilution with the 1ppm standard and their tankwater (assuming the tankwater reads 0)?

i can... hopefully tonight.. just been super busy and haven't been home.... working long hours..:( like that's a bad thing lol...

 

[sowellj]

I understand how that goes ... I was a week late in getting those standards out.

 

[Oiseau Reefer]

Did the tank water test ratio one 2one and low and behold I got .o6

 

[sowellj]

Oiseau, just to clarify - you did a 1:1 dilution of the 1 ppm standard and got a result of 0.06?

 

[jcom]

Sorry for the delay guys. Here are my results from Sowellj's standards:

Standard 1.0 = 0.93 Hanna
Standard 0.1 = 0.06 Hanna
Standard 0.01 = 0.00 Hanna

I guess I'll just figure that if I see zeros, I'll know my phosphates aren't much above 0.04 - 0.05. But if I see 0.01 or more, then I'll need to take action?? :squigglemouth:

 

[Oiseau Reefer]

Oiseau, just to clarify - you did a 1:1 dilution of the 1 ppm standard and got a result of 0.06?

That's correct what do you make of it did the test 3 times!!

 

[Der ABT]

so you guys still have a salifert or any other test kit to see what you would come up with on the color scale, Im still not sold on these but they dont seem to be too far off. I brought this up to one of the local store owners that sells the meter and he had not heard of any problems, which concerned me more.

Thanks for doing all the testing, making standards, etc you guys.....makes an informed purchase much easier if i ever pull the trigger

 

[sowellj]

Here is what I think. Their test works like this: Phosphate is converted to this inorganic acid. That acid is then reduced by vitamin C to form this blue colored product. The more phosphate .. the darker the blue color. Light is passed through this blue sample and the amount of light absorbed is proportional to the amount of phosphate in the sample. The problem I see with this is that there are likely things present (trace iron, etc) in our tank that limit vitamin C (ascorbic acid) ability to reduce the intermediate inorganic acid. Consequently, you can greatly underestimate the amount of phosphate present. I doubt Hanna will provide much in the way of what their reagents truly are for proprietary reasons. Nonetheless it would be great if the rep could chime in on this.

If the others could also do this test that would be great.

I must say it is a bit disconcerting that results could be off as much as an order of magnitude.

 

[sowellj]

Anyone deal with Hanna directly? Are they open to discussion? Maybe I can try and get in touch with their chemistry folks. No idea if the Hanna folks are aware of this thread, but if so maybe they could pm or chime in verify if what I am suggesting is a possibility.

 

[ronnie]

Their rep has been on here I believe? I think her name is Jessica.

 

[jcom]

Sowellj, check out post #216 which is from Jessica, the Hanna rep. Troylee has her email address as well, which may be the best way to contact her as I'm sure she's not checking this thread.

Kudos again on the standards! Very nicely packaqed and well prepared...you went above and beyond the call of duty! :bigsmile:

 

[sowellj]

Sorry for the delay guys. Here are my results from Sowellj's standards:

Standard 1.0 = 0.93 Hanna
Standard 0.1 = 0.06 Hanna
Standard 0.01 = 0.00 Hanna

I guess I'll just figure that if I see zeros, I'll know my phosphates aren't much above 0.04 - 0.05. But if I see 0.01 or more, then I'll need to take action?? :squigglemouth:

I don't like that they give the range as 0 to 2.5 ppm ... Even in neat solution it looks like their low end reliability is around 0.1 ppm. Even that is off a good bit. Given Oiseaus result, I don't think I have a lot of confidence in these. I have some ideas on how to maybe get around this, but, these are just based on how I am guessing that their meter works.

 

[melev]

One of you should ship your meter to sowellj so he can run a battery of tests. Or perhaps several of you could send him one to measure consistency between meters.

 

[sowellj]

One of you should ship your meter to sowellj so he can run a battery of tests. Or perhaps several of you could send him one to measure consistency between meters.

... or the Hannah folks .. their meter my chemicals?

 

[sowellj]

Sowellj, check out post #216 which is from Jessica, the Hanna rep. Troylee has her email address as well, which may be the best way to contact her as I'm sure she's not checking this thread.

Kudos again on the standards! Very nicely packaqed and well prepared...you went above and beyond the call of duty! :bigsmile:

No problem at all. I was a little shy about shipping them. When I was a grad student I was doing a little side work for the FBI. Shortly after 9/11 my prof sent them some solutions and did not send it through 'official' channels. The contents broke during shipping and emitted a foul odor. The entire FBI academy was evacuated as a result. They were not amused.

 

[Oiseau Reefer]

I don't like that they give the range as 0 to 2.5 ppm ... Even in neat solution it looks like their low end reliability is around 0.1 ppm. Even that is off a good bit. Given Oiseaus result, I don't think I have a lot of confidence in these. I have some ideas on how to maybe get around this, but, these are just based on how I am guessing that their meter works.

How would you get around what it is you're thinking of getting around clarification please

 

[sowellj]

No idea if it would work, but I am guessing that the ascorbic acid is being consumed by things other than its 'target'. One of the species that can do this is transition metals. You could add a metal chelator prior to analysis to prevent this. Having said that, I really don't know why the meters appear not to work well with a 'real sample' (as opposed to a neat standard). I chatted with some folks from the chemistry forum on RC and another issue these things have is sample turbidity. Filtering the samples prior to anlaysis can apparently help. But, most people don't have this capability, so it is somewhat academic.

Another thing for people to try is do the 1:1 dilution with tank water as well as fresh saltwater.

 

[shapermike]

I Have the big meter and I tested my tank and I always do it 2 times and I then send out my water to be tested and it was the same. I do calibrate my meter with Fresh DI water to get zeroed.

 

[Troylee]

Man I will try tonight sowellj.... Just working non stop and barely feed the tank lately lol....
I go in a 4am and work till 5pm then off to my sons baseball untill 9pm and do it all over the next day...:( guess I shouldn't complain good money right before Christmas lol...